The present invention relates to a cable guide for a sealed box and to a sealing assembly including such a guide.
More precisely, the invention relates to a cable guide, in particular for an optical or electrical cable for telecommunications, the guide comprising a cylindrical portion for coming into abutment via one of its ends against a sealing gasket for mounting in an inlet to a sealed box for protecting splices and containing a gas under pressure, the gasket being mounted in a tubular passage integral with the box and being designed to have its opposite end subjected to thrust by a nut screwed onto said passage.
Such a guide is known from patent document EP-0 942 507.
That document describes a sealed equipment box with a cable access comprising a sealing assembly constituted by a presser device mounted at the end of the tubular passage for compressing a gasket installed around the cable. The presser device has a nut for screwing onto the end of the tubular passage and a presser bushing, commonly referred to as a xe2x80x9ccable guidexe2x80x9d or a xe2x80x9cpresserxe2x80x9d, inserted between the nut and the gasket. The bushing has a projecting central cylindrical portion enabling it to come peripherally into abutment at one end against an internal bearing ring in the nut and at the other end against a sleeve via a cylindrical portion. The guide is thus constituted by a cylindrical sleeve that does not come directly into contact with the cable.
In the event of the cable bending outside the box, e.g. when the cable is handled or when it needs to be curved for connection purposes, a force is applied to the end of the gasket and its internal bore is therefore deformed radially, with this releasing a gap between the bore and the cable that can give rise to leakage of the gas under pressure.
The invention solves this problem and to do this, according to the invention, the cylindrical portion of the guide is extended away from the box by at least one radially deformable frustoconical tongue having at its end a clamping portion for clamping onto the periphery of the cable.
Thus, the cable is held via the clamping portion at a position that is relatively far away from the gasket and as a result, in the event of the cable being bent, said clamping portion absorbs the deforming forces and avoids deformation occurring inside the gasket, thereby eliminating any risk of leakage.
Furthermore, given their elasticity, the tongues can adapt to a range of cable diameters, and the gasket is no longer dependent on a particular cable diameter.
In a preferred embodiment, said guide has at least two tongues distributed around the periphery of its end remote from the box.
In this way, the cable is held around its entire periphery ensuring that it is secured regardless of the direction in which bending might be applied.
Preferably, said clamping portion has locking teeth on its inside face directed towards the cable.
When the clamp is clamped onto the cable, these teeth bite into the covering of the cable and lock onto it.
Advantageously, a clamping collar is associated with said guide so as to be clamped onto said clamping portion.
The collar enables the clamping proton to be clamped in a manner that is particularly simple and effective.
Preferably, the guide has at least one locking spline on its end face directed towards the box.
This spline is designed to become anchored in the gasket and to prevent the cable from turning while the nut is being tightened.
The invention also provides a sealing assembly for cables, in particular an optical or electrical cable for telecommunications, the assembly being designed for mounting at the inlet of a sealed box for protecting splices and containing a gas under pressure, the assembly including a guide as described above.
In particular, said guide has at least one locking spline on its end face directed towards the box, the spline being designed to anchor in a sealing gasket placed in said tubular passage and prevented from rotating therein by an arrangement of associated splines and grooves, the guide being designed to have its opposite end subjected to thrust from a nut screwed onto said tubular passage.